1. Field of the Invention
This invention relates more particularly to static-type signature verification systems. Nevertheless, the invention is also applicable for mixed-type signature verification systems in which static parameters and dynamic parameters are processed.
2. Description of the Prior Art
A static signature verification system processes handwritten signatures appended to base materials such as paper documents. The system is designed to authenticate signatures, i.e. to verify their conformity, by comparison with reference signatures recorded previously in the system. The signatures are represented by static parameters relating notably to shapes and dimensions of their drawings.
An important field of application of static signature verification is that of the verification of signatures appended to bank checks. In fact, in banking institutions, the signatures appended to checks are not systematically verified due to the very high cost that manual verification would entail. Only signatures on checks for large amounts or corresponding to particular bank accounts are verified. Banking institutions incur significant financial losses as a result of falsified checks. Automation of verification operations would enable systematic verification of signatures on checks and is therefore the solution required to avoid such losses.
Another field of application of static signature verification is that of the biometrical authentication of people. In fact, by adding a static verification of the drawing of a signature subsequent to a dynamic verification as the signature is written, the performances of a verification system are very substantially improved due to the fact that it is virtually impossible for a counterfeiter to imitate both the stroke speed and the drawing of a signature.
The different static signature verification systems currently available are of Anglo-saxon origin. These systems have the disadvantage of having been devised more specifically for processing Anglo-Saxon-type signatures, which are mainly cursive signatures. Mediocre performances are obtained with French signatures, and more generally with signatures of Latin origin, due to these signatures being of different types, cursive, graphic and mixed (cursive-graphic).
A further disadvantage of these systems is that the assembly of parameters used to represent the signatures is determined for once and for all and does not vary from one person to the next. Such an approach is open to criticism since the reliability of a parameter varies substantially from one person to the next and a very stable parameter for one person is sometimes very variable for another person.